Along with the 4th generation Glock pistol, Glock has launched two new 10mm Auto pistols: the Glock 20 SF and Glock 29 SF. The SF designation is often mistakenly said to stand for “Slim Frame” or “Small Frame”. It actually stands for “Short Frame”. The SF frames provide a small diameter grip. This makes it easier for people with smaller hands (or in this case normal hands to reach the trigger and is more comfortable to hold. The G20 SF and G29 SF apparently feel a lot more like the G17 in the hand than their standard frame contempories. From the press release:
Team GLOCK Shooting Squad Captain and Champion shooter Dave Sevigny adds, “I really like the SF design since it approaches the ‘feel’ of the G34, G35 and G17 I have been so fortunate with while competing. GLOCK has another winner here. These pistols will appeal to those who want a powerful cartridge for Law Enforcement, self defense and hunting. Best of all, they have the other GLOCK qualities of reliability, tough Tenifer finish and the controllable GLOCK ‘Safe Action’ fire control system that is successful around the world.” .

GLOCK 29SF
Multi purpose 10
Superior versatility in the high-performance
caliber 10mm: through reduced dimensions
compared with the standard size GLOCK 20,
the subcompact GLOCK 29 is also suitable for
concealed carry. In addition to the use as backup weapon for hunting, more and more security personnel on patrol duty appreciate the comfortable firing characteristics and the grip ergonomics of the GLOCK 29 with a standard magazine capacity of 10 rounds.